Sharing resources in networked computers, such as processors, computer memories, network bandwidth and data storage facilities, can increase efficiency by reducing maintenance and operating costs, allowing flexibility with respect to individual resource usage, and simplifying resource management. With respect to shared storage, the benefits include data consolidation, universal access to data, ease of storage management, and support for live migration of virtual machines (VMs) for virtualized environments.
A set of hardware computing platforms can be organized as a server cluster to provide computing resources for resource sharing. These server clusters can be organized in a data center. In addition, supporting technology (i.e., virtualization machine manager) can move running VMs between servers in the cluster. Additionally, the virtual machine manager (VMM) can determine initial and ongoing locations of virtual machines on hardware computing platforms in the server cluster, and can manage the allocation of cluster computing resources in accordance with constraints and objectives. In addition, the server cluster virtualization management software can request that a server in the cluster power itself down, and can use mechanisms to remotely power-on a server that is powered down. Server clusters consume significant power. The cost of that power is a major expense in operating a server cluster, and generating that power can have an environmental impact.